Lawn mower sharpening machine



Jan. 3, i939. P4 CARPENTER 2,342,569

LAWN MOWER SHARPENING MACHINE Filed Jan. 3l, 1936 4 Sheets-Sheet l A TTORNEYS.

.Fam 3, 1939.

P, CARPENTER LAWN MOWER SHARPENING MACHINE Filed Jan. 3l, 1936 4 Sl'xeetS-'Sheeffl 2 BY Mw A TTORNEYS.

P. CARPENTER im., 3, w39.

LAWN MOWER SHARPENING MACHINE l' Filed Jan. 3l, 1936 4 Sheets-Sheet 5 INVENTOR. %/d"0/w af/e/zzew A TTORNEYS.

.Fam 3, 1939,. P. CARPENTER 2,142,669

LAWN MOWEH SHARPENING MACHINE Filed Jan. 5l, 1956 -4 Sheets-Sheet 4 A TTORNE YS.

I Patented 3, 1939 treo sm'rss clientes PATENT e orri This invention relates to e. lawn mower sharpening machine; and has for one of its objects the provision of a. mounting for at one time sup- Another object of the invention is en arrsngement by which en edge with e uniform hevel .across the seme may he obtained along hoth the rotary sind the straight edged lsnie portions of the lewn mower.

.smother object of theinve'ntion is the prohi vision oi en errangementfby which n skilled operator need not he employed :for sharpening et lawn mower.V

ririother object of the invention is the ease of movement oi the shsrpening tool along the work.

Another object of the invention is a universal adjustment hy which the work cradle may he moved to different heights or towards or from the worir in order that the desired 'position may be obtained, and when once set will remain set st o predetermined point for sharpening ell of the dierent blades of the rotary unit.

With these and other objects in view, the invention consists oi certain novel features of construction, es will be more fully described, and particularly pointed out in the appended claims.

-In the 'accompanying drawings:

Fig. 1 is a sectional view of my machine illustrating in dotted lines the rotary portion of a lawn mower as in position for sharpeningj Fig. 2 is a similar view showing the work cradle as moved to a. different position and showing in this position the straight edged portion of the lawnmower es mounted in operating or working position;

Fig. 3 is a top plan view of the carriage for the grinding tool and its mounting;

Fig. d is a sectional view on the dot dash line of .Figure l looking in the direction of theorrow;

looking at it from the front of the machine in theposition shown in Figure 2;

Fig. 6 is a sectional View on line 5 5 of Figure 5;

50 Fig. 7 is a top' plan view of a iragmental., portion of the machine showing the relative con-` y Fig. 5 is an elevational view of the work cradle f In the use of lawn mower sharpening machines,

it is frequently necessary in the machines which are now in use to separably mount the rotary cutting member in its position in the machine end the straight edged portion of the mower, ne- 5 oessitating dierent adjustments for the work carriage. In order thet these two parts which ere necessary to grind or sharpen may be mounted in the'machine et the saine time, I have provided a cradle which will cerryboth or these lo parts and which may he operated. so that either one or the other may he selectivelybrought into engagement with the sharpening tool for operation or" this tool on the worir; and i lieve also so mounted the operating tool that the motor i5 which drives it moves with it in e more or less counterlzzalanced relation so that easy movement l of the tool may be had; and the following is s more detailed description ofthe present embodiment of this invention illustrating the preferred 2o means by which these advantageous results may be accomplished:

. With reference to the drawings, have provided two standards i@ which are connected together by iourlrigid bars li, l2, it and it, to 25 hold these standards in the desired spaced rele.- tion.- The rod l2 is in effect a track upon which there is mounted a. pair of brackets l 5 which support a. platform i6 of the carriage which may be tilted about the rod l2 or track, as a center, and 30 is also slidable therealong.A

Upon this carriage an electric motor il is mounted at one side of the track l2, while a grinding wheel or tool I8 is located at the other side of the tra-ck and is mounted in bearings I9; 35 in the carriage `et either side of a. suitable slot provided in the platform of the carriage. A suitable belt 2i is trained about pulleys 22 and 23 to drive the grinding wheel or tool from the motor i1. i

A .guard 24 is securely mounted on the carriage and is positioned about the Wheel having an opening receiving the shaft 25 upon which the wheel is mounted and with its sides 26 just inside of the bearings vfor the shaft25. Arod 45 21 extends upwardly sub-vertically from this guard and through a. sleeve 28 which is slidingly and rockablymounted upon the guide rod Il. A collar 29 may be held in position on the rod 21 by a wing nut 30 to engage the top of this sleeve 50 28 and limit the downward movement of the rod and thus limit the movement of the tool L8 towards the work by a very rm support; or if desired. set screws 3| in the sleeve 28 may hold the rod 21 in its setr position. Anut 32 held in the 66 slot 38 in the upper portion of the guard threadingly engages the rod 21 so that final adjustment as to position of the wheel may be had.

Shafts 86, 88' are mounted in each of the standards at the ends ofthe machine and upon each of these shafts there is mounted a drum 81 over which a flexible cord 88 is trained with a sufficient number of turns to obtain the desired friction against slipping. 'I'he opposite ends of this cord are attached to the carriage as at 89 and 40, the same vbeing adjusted as to tension by the turn buckle Il. Rotation ofthe shaft 36 by the handle 42 and crank arm 43 serves to move the carriage back and forth across the machine in accordance with the direction of manual manipulation.

Upon the rod I3 a pair of T-shaped sockets I5 are mounted from which rod 4B extends forwardly. At the forward ends of this rod 46 a member E1 is mounted having bifurcated arms 8. Between these arms a swivel 4S is mounted on gimbals consisting of a pair of threaded members having conical'pivot ends so that the swivel may operate. A threaded shaft 52 is rotatably held in this member and may be turned by a handle E3 and crank arm 51. This shaft-extends'through a threaded sleeve or nut 55 slidingly and swingingly mounted upon the shaft Il by means of the sleeve 56.V Thus as this threaded shaft 52 is turned, the rod B6 may raised or lowered, as desired.

-At a point spaced from the end of the rod 46,'

I have provided a member 68, the shape of which is best shown in Figure 7, through which there extends a rod 5| at right angles to the rod 46. This member $8 is provided with a nut portion 62 receiving the threaded shaft 63 which is mounted in the boss 64 carried by the member l1, which threaded shaft may be turned by means of a' handle 65 am'. crank arm 86. This member also carries a threaded pin G1 secured in the threaded opening 68 and. on which there is mounted a wing nut 69 for the purposes presently described. The rod 8| may be moved backwards or forwardly in the machine by rotation of the handle 65 or it may be moved upwardly or downwardly Vby reason of its being carried by the rod 46 which may be moved up-and down by means of a handle 53.

I have mounted upon the rod 8| which is capable of the up and down, forward and backward movements a pair of V-shaped members designated generally 1I! and having arms 1| and The arms 1| are connectedftogether at their ends by an angle iron 13 which is cut away from its lower or right angular junction of its parts,'as at 14, so as to provide aslot: and I have mounted in this slot arms 15 which fit within the V and which are held in position bya clamp plate 16 and threaded bolt 11 extending through the slot and into a portion at the lower end of one of the arms 15. Each of these arms is provided with a sleeve-like end 18 through which the threaded rod 19 extends with its conical end 8U providing a center for the mounting of the holder 8| of the straight edged portion 82 of the lawn mower which is to be sharpened;

and which is shown in working position in Flgerence to the grinding wheel I8 sothat theproper bevel desired may be obtained. 4

This V-shaped member is held in its 'desired position as shown in Figure 2, by setting up the wing nut 69, see Figure 2 and Figure 8, when the slot 86 of the arm1| is moved into position so that it receives the pin 81.

After the straight edged blade of the lawn mower has been sharpened,.it is not necessary to remove it from the machine prior to sharpening the rotary portion, it being merely necessary to lift the wheel which may be easily done by tilting' its carriage, loosening the wing nut 69 and tilt-` ing the entire cradle formed by the V-member 10 backwardly into a position shown in Figure. 1, whereupon the notch 81 will now receive the pin 61 so that the wing nut may beagain tightened to hold the work cradle in its new position.

V'I'he `arm 12 is provided with a notch 88 in its end which receives a rod 89 of a part of the lawn mower, and this may be held in place by the nutoor screw Sil and clamp plate 9|; while another part of the lawn mower will be supported by the bar 92 having a crotch 93 formed by the arm 94 to receive the back roller of the lawn mower. This bar 92 is threadingly supported in a bracket 95 oscillatable about the-bar Il and adjustable by means of a slot 98 and set screw 91. The roller is shown in dotted lines at 88 and the general position of the lawn mower may be determined by the dot-dash lines in Figure 1. The rotary member or cutter 89 is shown with the grinding wheel I8.

The edge of the blade iis engaged by an arm shownin dotted lines at |00, which is mounted upon and swingable about the shaft 25 as a center and may be held in the desired position by the arcuate slot IBI and a set screw |02, shown in dotted lines in Figure 1. The end of this arm |03 engages the forward edge of the blade and as the wheel rotates in the direction of the arrow |04 will, of course, keep this work against this edge of the arm or guide finger, and as the wheel travels back and forth it will rotate or cause the helical blade of the rotary cutter to follow along and maintain its edge against the cutter in the desired adjusted position, which the same will assume for the proper bevel and shaping of its edge for cutting. v

By the arrangement above described, it will appear thatv I may mount both parts of the lawn vone of its blades4 extending upwardly towards mower to be sharpened in the machine and selectively place each in a position to be operated upon by the grinding wheel. Further, by the arrangement of the motor on one side and the grinding wheel on the other of a tiltable platform, the same is nicely balanced and may be easily moved transversely of the machine back and forth to accomplish its desired operation.

The foregoing description is directed solely towards the construction illustrated, but I desire it to be understood that I reserve the privilege of resorting to' all the mechanical changes to which the device is susceptible, the invention being defined and limited only by the terms of the appended claims.

I claim:

1. In a lawn mower sharpening machine, a frame, an abrasive tool supported thereon, a work cradle provided with two independent supports one for the rotary cutter blade and the other for the straight edge cutter blade of the lawn mower, and means for rockably mounting the cradle on the frame for'selectively presenting either oi said supports in proximity to the tool for grinding the Work thereon.

2. In a lawn mower sharpening machine, a frame, an abrasivel tool supported thereon, a work cradle provided with two independent supportseach comprising pairs of arms one for the rotary cutter blade and the otherfor the straight edge cutter blade of the lawn mower, and means for rockablyV mounting the cradle on the frame for selectively presenting either of said supports in proximity to the tool for grinding the work thereon, said arms being located generally radially with respect to the axis of the rockable support. f

3. In a lawn mower sharpening machine, a frame, an abrasive tool supported thereon, a work cradle provided with two independent supports one for the rotary cutter blade and the other for the straight edge cutter blade of the lawn mower, and means for rockably mounting the cradlle on the frame for selectively presenting either of said supports in proximity to the tool for grinding the worln thereon, said support for the straight edge cutting blade comprising means to support the blade in two different right angular positions. i i

4. In a lawn mower sharpening machine, means for mounting the work, a tool carriage, a.

single track for the carriage, said carriage being substantially wholly supported by said track but tiltable about said track as a center and slightly overbalanced on one side, a tool carried by said carriage on the overbalanced side, a guide pmalsubstantially wholly supported by said track lbut' tiltable about said track as a center and slightly overbalanced on one side, a tool and a motor for driving the same both being mounted on said carriage, one on onel side of the pivotal mounting and the other on the other side thereof `in a relation to etl'ect a counterbalancing' action with the tool on the overbaianced side, a guide parailel with said track at a diierent horizontal level, and ,adjustable means slidably secured to said guide and secured to said carriage at the overbaianced. side to maintain the carriage in its adjusted position about its track.

6. In a lawn mower sharpening machine, means for mounting the Work, a tool carriage, a single track for the carriage, said carriage being substantially'wholly supported by said track but tiltable about said track as a center, a tool caxried by said carriage, a guide parallel with said track at a dierent horizontal level, and adjustable means slidably secured to said guide and secured to said carriage to maintain the carriage in its adjusted position of tilt about its track.

PURDOM' CARPENTER. 

